HAVRE DE GRACE (Oct. 27, 2009) - Biologists from the Maryland Department of Natural Resources stood knee deep in cold water Friday afternoon, pawing through the contents of a seine net, searching for a species of fish that many believe could be extinct.

They tossed brightly colored leaves unceremoniously back into the stream at Susquehanna State Park in Havre de Grace, but each tiny fish was inspected. There were plenty of them—many of them belonging to the darter family.

But, by late Friday evening, they hadn't found the right tiny darter.

The biologists were searching for the very small, "very, very rare" Maryland darter. The fish is so difficult to find that it has not been seen since 1988 and is listed on the endangered species list.

"The Maryland darter is unique to Maryland," said Jay Kilian, a DNR biologist. "It is Maryland's only unique fish."

As the biologists started the search, no one actually seemed to believe the fish would be found that day—but the sliver of hope remained.

"This darter has always been rare," said Richard Raesly, a professor at Frostburg State University. "The species has been found so irregularly."

Raesly was the last person to have documented a sighting of the darter, back in 1988 in Deer Creek—the same creek biologists were searching. The fish's disappearing act is not out of keeping with its past behavior, Raesly said. The fish went unseen between 1912 and the 1960s. There have been lots of gaps in Maryland darter sightings over the years, Raesly said.

The search was underway because U.S. Fish and Wildlife wants to know the status of the fish, which is protected by federal law under the Endangered Species Act, Kilian said.

"They want a definite answer," Kilian said.

Another reason DNR decided to mount the search for the darter again, according to Kilian, was because a new technique has been developed for catching bottom-dwelling fish like the darter.

For each stretch of creek, two people holding a rectangular net with poles on the short edges would set their net firmly into the bottom. A larger group of people from about 10 feet away would tramp their feet through the water, ostensibly to herd the fish into the net. In each group of herders, one biologist with a Ghostbusters-esque silver machine strapped to his back and a long rod with the net on the end would emit a low-level electrical buzz in the water, which, Kilian said, stuns the fish temporarily.

"With this new technique we have better hope that we might be able to find one," Kilian said.

A Marshall University scientist has developed a similar technique, involving an electrified trawl net dragged behind a boat for use in larger, more open areas. Thanks to a U.S. Fish and Wildlife grant, the boat will trawl for the Maryland darter in the Susquehanna River.

"Our biggest hope is that it may actually be found in the main body of the Susquehanna River," Raesly said.

In Pennsylvania, a similar trawl has been able to find fish that, like the Maryland darter, are extremely rare, DNR biologist Scott Stranko said.

"That's what gives us hope.... We sort of have a history of coming up with things that haven't been seen in a while," said Stranko. "It could happen."